1. Field of the Invention
The embodiments of the invention generally relate to on-chip temperature sensors, and more particularly, to an improved on-chip temperature circuit based on bolometry.
2. Description of the Related Art
On-chip temperature sensors are used for various purposes in very large scale integrated circuit (VLSI) technology. For example, temperature sensors are often used to trigger evasive actions to avoid overheating or for diagnostic purposes. Such thermal sensors can take many forms. For example, resistors, diodes, or any other temperature sensitive elements can be used as thermal sensors. Typically, pn junction diodes have been used because of the nearly ideal behavior of the forward conduction state in such pn junction diodes. That is, j=j0 exp(Vf Qe/(n k T)), n˜1. However, in silicon-on-insulator (SOI) technology, n is typically a few percent above unity and may also have a significant process tolerance. As a result, extra calibration measurements may be required in order to use this technique for temperature measurement in conjunction with SOI technology. Such extra calibration measurements increase the cost of implementation and, thus, limit the use of this temperature sensing technique. Therefore, there is a need in the art for an improved on-chip temperature sensor and, particularly, for an improved on-chip sensor suitable for use in SOI technology.